Water and properties/uses and Aqueous solutions Flashcards
Explain mp, density, and surface tension in relation to water
Melting point (high)
-hydrogen bonds dipole dipole and dispursion
-each molecule can potentially make 4 hydrogen bonds
Density
-decreases when water=solid (more formed hydrogen bonds)
-forms hexagonal shape which cretaes open space between molecules than liquid = less dense
High surface tension
-resistence of a liduid to increase SA
-forces of attraction occur in all directions in water–>no net force
-surface is providing a downward force (no molecules above)
-water has strong hydrogen bonds = high surface tension
Structure of water
-polar molecules
-permanent dipole
-main intermolecular force=hydrogen bonding
-high mp and bp
-density
-high surface tension
What is capillary action? How does it occur?
Movement of a liquid through/along the surface of another material despite other forces
-cohesive force
-adhesive force
-surface force
Define cohesive force
Intermolecular force between same type molecules
Define adhesive force
Forces of attraction between unlike molecules
Define surface tension
Due to cohesive forces at the surface of material and results in the surface of fluid being under tension
-resistance of a liquid to a change in SA
What is a universal solvent? Link to temperature and actions
Pure water
-can dissolve and transport a range of material across the wholeplanet and each cell of a living organism
-from 0-100 degrees usually
-can be a solvent over this temp range
Define aqueous solution.
Solutions where the solvent is always water
Homogenous vs heterogenous solution
Homogenous
Uniform properties and composition throughout thus solute and solvent are indistinguishable
Heterogenous
No uniform composition and visible distinguishable parts
Define dissolution
Dissolving a substance in another
Define miscible
Liquids that mix/can be dissolved
What is the dissolving process?
- Forces holding the solute together must be broken
- Forces holding together solvent must be broken
- Forces holding solute + solvent together must form
What makes a substance soluble?
The solute solvent interactions (or product) must be stronger than the solute solute and solvent solvent interactions.
i.e. like dissolves like-polarity
How does water dissolve molecular substances?
-molecule must have sufficient hydrogen bonds in order to dissolve in water
.to make it polar because like dissolves like
-if molecule= large it must have hydrogen bonds across entirety
-if not, it will no fully dissolve
Define water dissolving ionic compounds
Process dissolving solid ionic compounds in water and separating the positive and negative ions
Explain the attraction of solid ionic compounds in water
Ion-dipole attraction between the ion and corresponding charge of a water molecule
-if the attraction is strong enough water mol. will pull ion from lattice into the solution
-water mols. then surround ion which are then said to be hydrated
Explain the process of water dissolving an ion
- ionic bond is broken in ionic solid
- hydrogen bonds are broken in water molecule
- Many ion-dipole attractions formed between ion and water molecules
What is a saturated solution?
A solution containing a maximum amount of solute that is able to dissolve
-any more solute added will sit as crystals
What is an unsaturated solution?
a solution in which more solute can be dissolved.
-thus will be below the curve
What is a super saturated solution?
a solution that contains more than the average solvent that can be dissolved at a given temperature
-above the curve
-unstable
Define precipitate?
Insoluble solid products
-usually cloudy/white
Define spectator ion
Ion not involved in the reaction
Define concentration
Quantity of solute dissolved in a given amount of solution/solvent
Define dilute
Small amount of solute dissolved in large volume of solvent
Define concentrated
Large solute dissolved in small volume of solvent
Equation for Concentration with parts per million (ppm)
conc. ppm = mass of solute (mg) / mass of solution (kg)
Equation for Concentration with gram per litre (gL-1)
conc. of solution (gL-1) = mass of solute (g) / volume of solution (L)
Equation for Concentration with Mole per Litre (mol L-1)
conc. of solution in mol per litre = mol solute (mol) / volume of solution (L)
Define molarity
Measurement of concentration of a solution
Relationships between dilution and conc + vol
As the amount of solute stays unchanged, the number of moles of the solute will not change but the conc and volume will
